Birubius batei (Haswell 1879)

Birubius batei (Haswell)

Phoxus Batei Haswell, 1879:259–260, pl. 9: fig. 3; 1882:237–238.

Pontharpinia rostrata.—Stebbing, 1906:146–147 [in part]; 1910:635.

NOMENCLATURE.—The so-called type material of this species (AM, P.3438, Port Jackson) is confounded. The specimens in the collection are Matong matong, new species, and clearly not what Haswell described and illustrated (Barnard and Drummond, 1976, erroneously labeled this taxon as “Birubius sp.”). There is strong evidence that the material under consideration was labeled as “Type” by a person other than Haswell more than 20 years after his publication (see J. L. Barnard, 1974). We therefore reject that material as being the legitimate type of Birubius batei. On the other hand we hesitate in creating a neotype for this species; instead, we have designated a “Main Voucher.” We have material, from Botany Bay, a locality near Port Jackson, that fits Haswell's meager description, but believe that a precise survey of the Port Jackson area should be undertaken to find what lives there today. Another of our species, B. jirrandus (30), also fits the description of B. batei but has not, as yet, been found in the vicinity of Port Jackson, New South Wales.

DESCRIPTION OF FEMALE.—Head about 25 percent of total body length, greatest width about 65 percent of length; rostrum weakly constricted, narrow, reaching middle of article 2 on antenna 1. Eyes medium, largely occluded with pigment. Article 1 on peduncle of antenna 1 about 1.5 times as long as wide, about 2.4 times as wide as article 2, ventral margin with about 10 setules, weakly produced dorsal apex with 3–4 setules (only 2 showing in illustration); article 2 about 0.55 times as long as article 1, with ventral proximal cycle of 7 setae; primary flagellum with 12 articles, about 0.85 times as long as peduncle, lacking aesthetascs; accessory flagellum with 10 articles. Spine formula on article 4 of antenna 2 = 1–3–4–3, dorsal margin with notch bearing 3 setae and spines, ventral margin with 6 groups of 2 long to short setae, one ventrodistal long spine; article 5 about 0.8 times as long as article 4, facial spine formula = 1–2–2, dorsal margin bearing group of setules, ventral margin with 4 sets of 2–3 long to short setae, 3 ventrodistal long to medium spines; flagellum about 1.3 times as long as articles 4–5 of peduncle combined, with 13 articles. Mandibles with medium palpar hump; right incisor with 3 teeth and notch; left incisor with 3 teeth in 2 branches; right lacinia mobilis bifid, distal branch simple, shorter than proximal, proximal branch simple, pointed; left lacinia mobilis with 4 teeth plus one accessory tooth; right rakers 8; left rakers 9; molar in form of elongate plaque, molars with 8 primarily long spines, no spine disjunct, each molar with plume; palp article 1 short, article 2 with one long inner apical seta and 3 other short inner setae and 2 outer setae, article 3 about as long as article 2, oblique apex with 10 spine-setae, basofacial formula = 0. Inner plate of maxilla 1 large, bearing one long apicofacial pluseta, one shorter similar apicomedial seta, 2 apicolateral much shorter setae; palp article 2 with 2–3 apicalmedial marginal spines and 5–6 submarginal setae. Plates of maxilla 2 extending equally, of equal breadth, outer with 6 apicolateral setae, inner with 3 medial setae. Inner plate of maxilliped with one large thick apical spine, 2 apicofacial setae, 4 medial setae; outer plate with 6 medial and apical spines, 2 apicolateral setae; palp article 1 with 2 apicolateral setae, article 2 with 3 groups of one apicolateral seta each, medial margin of article 2 moderately setose, article 3 produced, with 4–5 facial setae, 2 lateral setae, nail of article 4 medium, with 2 accessory setules. Coxa 1 scarcely expanded distally, anterior margin almost straight, main ventral setae of coxae 1–4 = (5–6)–7–7–0, posteriormost seta of coxae 1–2 slightly shortened; anterior and posterior margins of coxa 4 divergent, posterior margin oblique, convex, posterodorsal corner rounded, posterodorsal margin short, almost straight, width–length ratio of coxa 4 = 7:8. Long posterior setae on article 2 of gnathopods 1–2 and pereopods 1–2 = 3–(5–6)–4–6, short anteriors = (10–11)–(8–9)–5–3, long anteriors = 3–(13–14)–0–0, gnathopod 1 with 3 long basofacial setae. Gnathopods ordinary; width ratios of articles 5–6 on gnathopods 1–2 = 24:30 and 26:33, length ratios = 65:60 and 58:57: palmar humps ordinary, palms oblique; article 5 of gnathopods 1–2 elongate, ovate, posterior margin flat. Pereopods 1–2 similar: pereopod 1 with supernumerary apicofacial setae on article 5, other facial setae formula on article 4 = 4 and 3, on article 5 = 5 and 6; main spine of article 5 extending to M. 75 on article 6, article 5 with 2 proximoposterior spines; spine formula of article 6 = 5 + 6 plus middistal seta; acclivity on inner margin of dactyls of pereopods 1–2 weak, emergent setule long, midfacial pluseta ordinary. Coxae 5–7 posteroventral setule formula = 4–3–4. Articles 4–5 of pereopods 3–4 broad, facial spine rows moderately developed, facial ridge formula on article 2 of pereopods 3–5 = 0–2–2, anterior ridge of pereopod 5 long, posterior ridge abutting; width ratios of articles 2, 4, 5, 6 of pereopod 3 = 41:40:34:16, of pereopod 4 = 67:39:26:14, of pereopod 5 = 77:26:19:9, length ratios of pereopod 3 = 78:34:43:42, of pereopod 4 = 90:52:41:54, of pereopod 5 = 102:36:28:20; article 2 of pereopod 5 reaching apex of article 4 (discounting special lobe); article 4 of pereopods 3 and 5 with especially elongate posterodistal lobe; medial apex of article 6 truncate, uncombed. Posteroventral corner of epimeron 1 rounded, posterior margin convex, bearing setule, corner with setules, anteroventral margin with 6 short setae, posteroventral margin with 2 long setae; posteroventral corner of epimeron 2 rounded, weakly protuberant, posterior margin undulant, with setule, facial setae = 8–10, posteriormost pair set vertically; posteroventral corner of epimeron 3 with small tooth, posterior margin straight, serrate, 7–8 setose, uppermost seta tiny, ventral margin with 3–4 posterior setae. Urosomite 1 with 2 long ventral spines at base of uropod 1, articulation line broken in middle; urosomite 3 weakly protuberant dorsally. Rami of uropods 1–2 with articulate enlarged apical nails, rami of uropods 1–2 lacking accessory nails, outer ramus of uropod 1 with 6–10 dorsal spines, inner with 2–4, outer ramus of uropod 2 with 4–8 dorsal spines, inner with 1–2 dorsomedial spines; peduncle of uropod 1 with 4–5 apicolateral spines and 4–5 basofacial setae, medially with 6 marginal setae and spines becoming thicker apically; peduncle of uropod 2 with 10–14 dorsal spines, medially with one small apical spinule. Peduncle of uropod 3 with 6 ventral spines, dorsally with one lateral spine, one medial spine; rami feminine, inner extending to M. 75 on article 1 of outer ramus, apex with 3 setae, medial margin with 3 setae, article 2 of outer ramus ordinary, 0.17, bearing 2 long setae, medial margin of article 1 with 2 setae, lateral margin with 5 acclivities, spine formula = 1–2–2–2–2–2, setal formula = 0–1–1–1–1–1. Telson ordinary, length–width ratio = 14:13, not fully cleft, each apex of medium width, rounded, lateral acclivity shallow, bearing ordinary lateral setule, spine next medial of length equal to setule, midlateral setules diverse. Cuticle with ordinary sparse bulbar setules, surface bearing fine striations in form of linear fingerprint pattern.

DESCRIPTION OF MALE.—Rostrum shorter than in female. Antenna 1 with one calceolus each on articles 1–4. Facial spine formula on article 4 of antenna 2 = 1–2–4–3, on article 5 = 2; article 5 with one dorsal set of male setae and one calceolus, ventrodistal apex with 2 thin spines and one setule, flagellar formula = 27, 2, 4, 6…24. Right and left rakers 8; basofacial setal formula of article 3 on mandibular palp = 1–2. Palp of maxilla 1 with 2 spines and 4 setae. Outer plate of maxilliped with one apicolateral seta. Coxa 4 like that of female but smaller in relation to coxa 1 than in female; ventral setal formula of coxae 1–4 = 4–6–6–0, setae short. Long posterior setae on article 2 of gnathopods 1–2 and pereopods 1–2 = 2–(2–3)–2–3 plus 2 basofacial setae on gnathopod 1, long anteriors = 3–7–0–0. Facial and setal-spine formulas of pereopods 1–2 on article 4 = 3 and 2, on article 5 = 5 and 5, on article 6 = 4 and 5 plus middistal seta. Article 2 of only pereopods 3 and 5 narrower than in female, pereopod 5 larger in relation to pereopod 3 than in female. Epimera 1–3 broadened, posterior margin of epimeron 3 shortened; setal formulas, epimeron 1 anteroventral = 5, posteroventral = 2, epimeron 2 facial = 7, epimeron 3 posterior = 8, facial = 1–2. Articulation lines of urosome strong, ventrolateral spine of urosomite 1 very small, dorsal base of urosomite 3 with hump. Spine formulas of uropods, uropod 1 peduncle apicolateral = 4–5, basofacial = 6, medial = 4 plus apical enlarged, uropod 2 peduncle dorsal = 11–14, dorsal spines on outer ramus of uropod 1 = 6–7, of uropod 2 = 5–6, inner ramus of uropod 1 = 2–3, of uropod 2 = 2 shortened, fully medial. Ventral spines on peduncle of uropod 3 = 6, spine formula on article 1 of outer ramus = 1–1–2–2–2–2, setal formula = 1–1–1–1–1–1. Telson slightly elongate, distal spines shortened.

OBSERVATIONS.—Dwarf males from Western Australia, WAM 414–73 (index “273”): Male “a.” 3.31 mm, and male “b,” 3.50 mm: nail on dactyl of maxilliped elongate, 60 percent as long as article 4; article 6 of gnathopod 2 stouter than in typical phenotype. Other descriptive features of male “a”: primary flagellum of antenna 1 with 10 articles, accessory flagellum with 7, primary with one calceolus each on articles 1–4. One aesthetasc each on articles 1–8; antenna 2 flagellar formula = 23, 2, 4, 6…20; article 4 of peduncle with spine formula of 3–4–3, article 5 with 2 facial spines and 2 sets of posterior setal spines; right lacinia mobilis of normal bifid form, mandibular palp article 2 with 3 medial setae and 2 apicomedial setae, article 3 with 7 apical setae, basofacial formula = 2–1; palp of maxilla 1 with 4 spines and 3 setae; setal formula of coxae 1–4 = 4–5–5–0; long posterior setae on article 2 of gnathopods 1–2 and pereopods 1–2 = 1–1–2–2, long anteriors = (2–3)–4–0–0, short anteriors = (0–1)–3–3–3, no others, facial setae on articles 4 and 5 of pereopods 1–2 = 2 and 3, spine formula of article 6 = 3 + 4 plus middistal seta; anterior ridge on article 2 of pereopod 5 of short form seen in Birubius jirrandus (30), pereopod 5 with 6 posterior teeth on article 2; epimeron 1 with 4 anteroventral setae, 2 posteroventral setae, epimeron 2 with 4 horizontal setae and pair set vertically, epimeron 3 with 6 posterior setae and one or no posteroventral seta; peduncle of uropod 1 with 2 basofacial setae, with 4 apicolateral spines, outer ramus with 6 dorsal spines, inner ramus with 2, peduncle of uropod 2 with 9 dorsal spines, outer ramus with 3, inner with one; outer ramus of uropod 3 with 4 acclivities, spine formula = 1–1–1–1–2, setal formula = 1–1–1–1–1. Male “b”: epimeron 1 with 4 anteroventral and 3 posteroventral setae, epimeron 2 with 5 horizontal setae and pair set vertically, epimeron 3 with 7 posterior and 2 posteroventral setae; peduncle of uropod 1 with 5 basofacial setae, peduncle of uropod 2 with 10 dorsal spines, outer ramus with 4; other counts similar to male “a”.

Our southeastern Australian material of Birubius batei? is mostly represented by giant specimens, whereas the dwarf western Australian males may represent a more average size for this species. Features of subspecific value between the two sets of specimens collected almost 2,000 miles apart include spine counts, the short ridge on pereopod 5, and the broadened hands on the gnathopods.

Males of WAM 414-73 (index “274”):Male “m,” 4.80 mm: subbifid apical branch of right lacinia mobilis (see illustration); antenna 2 normal; nail on maxillipedal palp almost 40 percent as long as article 4, thus slightly elongate; hand of gnathopod 1 almost normal, that of gnathopod 2 stout (see illustration); pereopod 5 normal; epimeron 1 with 5 anteroventral setae, 2 posteroventral submarginal setae, epimeron 2 with 5 horizontal and one dorsally thrust setae, epimeron 3 with 6 posterior and no ventral setae; peduncle of uropod 1 with 4–5 basofacial setae, 5 apicolateral spines, outer ramus with 6 spines, inner with 2, peduncle of uropod 2 with 11 spines, outer ramus with 3 dorsal spines and one spine fully inserted (non-emergent) in body of ramus, inner ramus with 2 spines; lateral apex of peduncle on uropod 3 with 2 spines, outer ramus with spine formula of 1–1–2–2–2–2, setal formula of 1–1–1–1–1–1; abnormalities are maxillipedal nail, gnathopod 2, outer ramus of uropod 2, peduncle of uropod 3. Male “n”: right lacinia mobilis normal; both hands of gnathopods stout; outer ramus of uropod 2 with 5 normal spines, inner with one; spine formula on outer ramus of uropod 3 = 2–1–1–1–2, setae = 0–2–1–1–1; abnormalities are gnathopods and outer ramus of uropod 3. Male “p”: Only hand of gnathopod 2 stout.

Males of WAM 414-73 (index “275”): Male “q”: right lacinia mobilis normal; maxillipedal nail normal; hands of both gnathopods slightly stoutened; anterior ridge of pereopod 5 normal; epimeron 1 with 5 anteroventral setae, with 2 posteroventral setae immediately adjacent to anteroventral set (abnormal), epimeron 2 with 6 horizontal setae and one thrust dorsally, epimeron 3 with 4 posterior setae confined ventrally, one posteroventral seta, one ventral seta-spine; peduncle of uropod 1 with 6 basofacial setae, lateral apex with 6 spines (one of these disjunct towards base), outer ramus with 5 spines, inner with one (abnormal), peduncle of uropod 2 with 11 spines, outer ramus with 4, inner with one; spine formula on outer ramus of uropod 3 = 1–1–1–2–2–2, setae = 0–1–1–1–1–1. Other males: epimeron 1 normal.

Abnormalities in Western Australian Males: Recombinations or gene flow in the direction of Birubius jirrandus (30) are seen in the shortened anterior ridge of pereopod 5 in “273” males, in the spine reduction on the inner ramus of uropod 1 on “275” males; but other abnormalities in maxillipedal nail, setal distribution on epimera 1–2, and right lacinia mobilis of one “274” male, all of which occur inconsistently, suggest that the two main differences listed in the discussion of this species and B. jirrandus are valid.

DESCRIPTION OF JUVENILE (juvenile “k,” 2.26 mm).—Head similar to that of adult but somewhat thinner from dorsal view. Antenna 1 with 8 articles in primary flagellum, 5 in accessory flagellum. Spine formula on article 4 of antenna 2 = 1–3–3–3, dorsal margin with 2 setae in notch, article 5 with 2 facial spines and 2 posterior sets of setae; flagellum 7-articulate. Upper lip and epistome lacking articulation. Right lacinia mobilis bifid, both branches conical; right mandible with 5 raker spines; molar with 3 spines, none disjunct (left mandible not examined); palp article 3 lacking basofacial setae. Lower lip and plates of maxilla 1 not examined; palp of maxilla 1 with 2 spines and 3 setae. Inner plate of maxilla 2 with one medial seta; outer plate with one apicolateral seta. Inner plate of maxilliped with one apical spine and one apicoventral seta, 2 medial and 2 dorsofacial setae; outer plate with 4 spines, no lateral setae; article 3 of palp with 2 facial setae. Setae of coxae 1–4 = 4–3–3–0. Article 2 of gnathopods 1–2 with 0 and 2 long posterior (see illustrations of gnathopods). Setal and spine formulas of pereopods 1–2, article 2, posterior long seta = 1, article 4 facial = 4, article 5 facial = 2, article 6 spines = 3 + 3 plus one seta, article 5 also bearing one proximal spine. Pereopods 3–4 generally similar to those of adult but with fewer spines and setae. Article 2 of pereopod 5 (illustrated) with stronger ventral setae than in adult (generally typical of juveniles in certain species). Epimeron 1 (illustrated) with one anteroventral seta, one posteroventral seta; epimeron 2 with 4 facial setae in tandem; epimeron 3 with 3 posterior setae and 2 setules, no facial setae. Urosomite 1 with one large ventral spine at base of each uropod 1 (not in adult). Uropod 1 with a basofacial seta, 1–2 apicolateral spines, outer ramus with 3 dorsal spines, inner with one dorsal spine; uropod 2 with 4–5 peduncular spines, outer ramus with 2 dorsal spines, inner with one dorsal spine. Uropod 3 and telson as illustrated.

Identification of juvenile with adult is strong but confounded by the relatively great length of the ventral setules on article 2 of pereopod 5. This anomaly can be shown in other species to be characteristic of youthful specimens in contrast to adults.

ILLUSTRATIONS.—The paired basofacial setae on article 3 of the maxillipedal palp in female “f” is an abnormal condition.

MAIN VOUCHER.—AM, female “f,” ovigerous, 5.39 mm.

LOCALITY.—EBS 200, 11 Apr 1973, off Towra Beach, Botany Bay, New South Wales, Australia, 2.7 m, sand.

VOUCHER MATERIAL.—EBS 362: male “z,” 5.50 mm (illus.); female “c,” 6.28 mm. EBS 199: female “d,” 6.10 mm. EBS 196: male “e,” 5.62 mm. WAM 414-73 (divided into 3 subsamples with indices): “273,” male “a,” 3.31 mm, male “b,” 3.50 mm; “274,” male “m,” 4.80 mm (illus.), male “n,” 4.70 mm (illus.), male “p,” 4.20 mm; “275,” male “q,” 4.36 mm; plus 3 other males. JLB AUS 13: juvenile “k,” 2.26 mm (illus.).

RELATIONSHIP.—Because the combination of noncrowded setae on epimeron 2, strong basofacial setae on uropod 1 and elongate wrists on the gnathopods prevents an evolutionary flow from the other 3 subgroups in this division, Birubius batei? and B. jirrandus (30) form a pair distinct from the other members of this division and apparently derive not from any of the other subgroups but directly from their hypothetical ancestor. Birubius batei? and B. jirrandus also differ from the other group in the absence of fully facial setae on epimeron 3 and in the presence of ventral setae, although the latter are almost facial.

In other ways this species appears very close to the B. kokorus group (25–27) but differs in the more numerous basofacial setae on uropod 1 and/or in the longer telsonic spines. From the B. lowannus group (22–23), B. batei? differs in the longer anterior ridge of pereopod 5, the uncrowded setae of epimeron 2, and the shorter article 2 on the outer ramus of uropod 3. From the B. gambodeni group (20–21) B. batei? differs in the more elongate wrists of the gnathopods and the longer anterior ridge on pereopod 5.

MATERIAL.—EBS, 20 samples (52); WAM, one sample (11); JLB AUS, one sample (1).

DISTRIBUTION.—New South Wales: Botany Bay, Lake Macquarie, and Jervis Bay, 0.3–6.0 m, coarse sand. Western Australia: Barrow Island, presumably surface nekton; and Middleton Beach, near Albany, intertidal.